CRITICAL CURRENT DENSITY ENHANCEMENT VIA INCORPORATION OF NANOSCALE Ba2(Y,RE)NbO6 IN REBCO FILMS

Abstract

A superconducting article includes a substrate having a biaxially textured surface, and an epitaxial biaxially textured superconducting film supported by the substrate. The epitaxial superconducting film includes particles of Ba 2 RENbO 6 and is characterized by a critical current density higher than 1 MA/cm 2 at 77K, self-field. In one embodiment the particles are assembled into columns. The particles and nanocolumns of Ba 2 RENbO 6 defects enhance flux pinning which results in improved critical current densities of the superconducting films. Methods of making superconducting films with Ba 2 RENbO 6 defects are also disclosed.

1 . An article comprising a substrate having a biaxially textured surface, and an epitaxial biaxially textured superconducting film supported by said substrate, said epitaxial superconducting film comprising nanoparticles of double perovskite, Ba 2 RENbO 6  and being characterized by a critical current density higher than 1 MA/cm 2  at 77K, self-field. 
     
     
         2 . An article in accordance with  claim 1 , wherein said substrate is selected from the group comprising of a single-crystal substrate, a RABiTS substrate, and an IBAD substrate. 
     
     
         3 . An article in accordance with  claim 1 , wherein said particles of Ba 2 RENbO 6  are in the form of aligned columns, aligned within 20 degrees from the c-axis of the superconducting film. 
     
     
         4 . An article in accordance with  claim 3 , wherein said columns are comprised of particles. 
     
     
         5 . An article in accordance with  claim 3 , wherein the columns are comprised of nanorods. 
     
     
         6 . An article in accordance with  claim 1 , wherein said superconducting film characterized by an I c  greater than 300 A/cm at 65K, 3 T. 
     
     
         7 . A method of making a superconducting article comprising a biaxially textured superconducting material and characterized by a critical current density higher than 1 MA/cm 2  at 77K, self-field, said method comprising the steps of (a) providing a buffered biaxially textured or single crystal substrate and (b) performing simultaneous deposition of the biaxially textured superconducting material and nanoparticles of double perovskite Ba 2 RENbO 6 . 
     
     
         8 . The method of  claim 7 , wherein said deposition step comprises an in-situ deposition process selected from the group consisting of pulsed laser ablation, chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), sputtering and e-beam co-evaporation. 
     
     
         9 . The method of  claim 7 , wherein said deposition step comprises an ex-situ deposition process selected from the group consisting of chemical solution processes, and an ex-situ BaF 2  process, followed by a heat treatment. 
     
     
         10 . The method of  claim 9 , wherein the chemical solution process is selected from the group consisting of TFA-MOD, non-fluorine MOD processes, and reduced fluorine MOD processes. 
     
     
         11 . A method of making a superconducting film comprising a biaxially textured superconducting material and characterized by a critical current density higher than 1 MA/cm 2  at 77K, self-field, said method comprising the steps of:
 (a) providing a buffered biaxially textured or single crystal substrate (b) heating the substrate to a preselected deposition temperature under a preselected gas atmosphere and pressure (c) performing simultaneous deposition of the biaxially textured superconducting material and nanoparticles of double perovskite Ba 2 RENbO 6 .   
     
     
         12 . A method in accordance with  claim 13  wherein the simultaneous deposition is done using an in-situ deposition process selected from the group consisting of pulsed laser ablation, chemical vapor deposition (CVD), metal organic chemical vapor deposition (MOCVD), sputtering and e-beam co-evaporation. 
     
     
         13 . A method in accordance with  claim 12  wherein the simultaneous deposition is done using an ex-situ deposition process selected from the group consisting of chemical solution processes, and an ex-situ BaF 2  process, followed by a heat treatment. 
     
     
         14 . The method of  claim 13 , wherein the chemical solution process is selected from the group consisting of TFA-MOD, non-fluorine MOD processes, and reduced fluorine MOD processes. 
     
     
         15 . A superconducting article comprising a biaxially textured superconducting composition containing RE, Ba, Cu and O and nanoparticles of double perovskite, Ba 2 (Y,RE)NbO 6  and being characterized by a critical current density higher than 1 MA/cm 2  at 77K, self-field. 
     
     
         16 . The superconducting article of  claim 15 , wherein the superconducting composition comprises REBCO. 
     
     
         17 . An article in accordance with  claim 15 , wherein said particles of Ba 2 RENbO 6  are in the form of aligned columns, aligned within 20 degrees from the c-axis of the superconducting film. 
     
     
         18 . An article in accordance with  claim 15 , wherein said columns are comprised of particles. 
     
     
         19 . An article in accordance with  claim 15 , wherein the columns are comprised of nanorods. 
     
     
         20 . An article in accordance with  claim 15 , wherein said superconducting film is characterized by an greater than 300 A/cm at 65K, 3 T.